Pars plana vitrectomy and re-directing a dexamethasone implant into vitreous cavity following misdirected entry into the crystalline lens
Partha Biswas1, Krishnendu Nandi2, Sneha Batra3, Aniket Ginodia3, Preeyam Biswas4 1 Director, B B Eye Foundation, Kolkata, India 2 Consultant, Vitreo-Retina Services, B B Eye Foundation, Kolkata, India 3 Fellow, B B Eye Foundation, Kolkata, India 4 M.S Student, D.Y Patil Medical College, Hospital & Research Centre, Pune, Maharashtra, India
Date of Submission
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Correspondence Address: Sneha Batra 39, Diamond Harbour Road, P.O. Barisha, Kolkata - 700 008, West Bengal India
Source of Support: None, Conflict of Interest: None
A known diabetic patient presented with diabetic macular edema (DME) and nonproliferative diabetic retinopathy in both eyes with a vision of 6/18, N12in the right eye and 4/60, N36in the left eye (LE). The patient had undergone injection of dexamethasone implant in the LE which got misdirected into the crystalline lens. The patient was taken up for phacoemulsification with intraocular lens implantation along with vitrectomy and posterior vitreous detachment induction, and redirection of the dexamethasone implant into the vitreous cavity. The DME resolved over the next 3 months.
Keywords: Dexamethasone implant, diabetic macular edema, foreign body in lens, intravitreal steroid, Ozurdex
How to cite this article: Biswas P, Nandi K, Batra S, Ginodia A, Biswas P. Pars plana vitrectomy and re-directing a dexamethasone implant into vitreous cavity following misdirected entry into the crystalline lens. Indian J Ophthalmol 2018;66:1033-6
How to cite this URL: Biswas P, Nandi K, Batra S, Ginodia A, Biswas P. Pars plana vitrectomy and re-directing a dexamethasone implant into vitreous cavity following misdirected entry into the crystalline lens. Indian J Ophthalmol [serial online] 2018 [cited 2022 May 23];66:1033-6. Available from: https://www.ijo.in/text.asp?2018/66/7/1033/234955
Ozurdex ® (Allergan, Irvine, CA) is a biodegradable sustained-release drug delivery system, which is implanted into the vitreous cavity, and releases 0.7 mg of dexamethasone into the vitreous cavity over a period of 3–6 months. It is currently approved by the US Food and Drug Administration for macular edema due to retinal vein occlusion, center-involving diabetic macular edema (DME), and noninfectious posterior uveitis.
Here, we report a case of misdirected intralenticular Ozurdex implant, which was managed by phacoemulsification and vitrectomy followed by repositioning of the same implant into the vitreous cavity.
A 51-year-old diabetic male presented to our outpatient department in October 2015 with complaints of dimness in vision in the left eye (LE) for the past 3 months. He had been diagnosed elsewhere to have DME in the LE and was administered injection dexamethasone intravitreal implant in the LE a week earlier.
His best-corrected visual acuity was recorded as 6/18, N12 in the right eye (RE), and 4/60, N36 in the LE. On slit lamp examination, there was stable pseudophakia with a quiet anterior chamber in the RE. In the LE, Grade II nuclear cataract was present, with a misdirected dexamethasone implant seen intralenticularly in the upper part of the lens [Figure 1]. Intraocular pressure was recorded as 14 and 16 mm of Hg in the RE and LE, respectively. On fundus examination, changes of mild nonproliferative diabetic retinopathy (NPDR) were found in the RE; in the LE, mild NPDR with clinically significant macular edema was seen [Figure 2].
Figure 1: Slit lamp photograph showing Ozurdex implant incarcerated in superotemporal part of the lens in the left eye
A macular scan was performed by the optical coherence tomography (OCT) (Optovue, Inc.) to further confirm these findings. In the LE, there was presence of macular edema, central macular thickness being 771 μ, along with taut posterior hyaloid membrane [Figure 3].
Figure 3: Optical coherence tomography macular scan of left eye showing center-involving macular edema (central macular thickness = 771 μ) with taut posterior hyaloid membrane
The patient was then taken up for a combined procedure: Phacoemulsification with implantation of an intraocular lens, as well as vitrectomy with removal of taut posterior hyaloid membrane, and repositioning of the misdirected dexamethasone implant into the vitreous cavity [Video 1].
An intact capsulorhexis is crucial to any phacoemulsification with a ruptured posterior capsule, and it was completed cautiously [Figure 4]a. Gentle and controlled hydrodissection and hydrodelineation were performed after manually separating the cortex from the anterior capsular rim with a spatula. The nucleus was rotated gently, taking care that the ruptured posterior capsule does not give away. Phacoemulsification was performed by direct chop technique.
Figure 4: Surgical steps during phacoemulsification: (a) Initiating capsulorhexis; (b) isolating lens matter with incarcerated implant; (c) using silicon-tipped needle for fine dissection; (d) safeguarding the implant in the angle of anterior chamber during phacoemulsification
It was a surgical challenge to preserve the small piece of lens matter containing the incarcerated dexamethasone implant, and this piece was tackled last during the phacoemulsification. The implant was found to be posteriorly placed in the cataractous lens [Figure 4]b, and dissection and phacoemulsification of this part was performed after the major part of the nucleus had been managed. Extreme care had to be taken so that the implant was not inadvertently damaged by the phaco probe. The Ozurdex containing nuclear fragment was dissected from the main nucleus with the help of a blunt metal spatula at first; subsequently, an atraumatic silicon tipped needle was used to very gently peel off the surrounding lens matter, while keeping the implant intact [Figure 4]c.
The fragile implant with a wisp of surrounding lens matter was pushed aside, and phacoemulsification proceeded. However, at one point the posterior capsule gave away, and some smaller nuclear fragments dropped into the vitreous cavity.
Anterior vitrectomy was performed and the remaining cortical matter was aspirated, temporarily protecting the implant unharmed near the angle of the anterior chamber covered adequately with viscoelastic substance [Figure 4]d.
A 23G pars plana vitrectomy was performed, removing the remnants of the lens matter from the vitreous cavity [Figure 5]. Posterior vitreous detachment was induced, and the epiretinal membrane was peeled. The implant was then very gently ushered into the vitreous cavity. A multi-piece foldable intraocular lens was placed in the sulcus to compartmentalize the anterior segment from the posterior segment.
Since very few such cases have been reported in literature before, the behavior of the re-injected implant could not be predicted. Subsequently, the patient was followed up at four weekly intervals with serial OCT scans as well as clinical examination. Over a period of 6 months, the macular edema gradually resolved, and the visual acuity recovered to 6/12, N10[Figure 6] and [Figure 7].
Figure 6: Fundus photograph of the left eye at follow-up after 1, 3, 6, and 8 months
Ozurdex is a biodegradable intravitreal implant, which releases 0.7 mg of dexamethasone into the vitreous cavity over a period of 3–6 months. It is preloaded into a single-use applicator to facilitate its administration into the vitreous cavity. It is an effective, safe, and long-lasting alternative to anti-vascular endothelial growth factor (VEGF) drugs, particularly in cases of refractory macular edema, pregnancy, and patients with previous history of thromboembolic episodes. However, due to its common side effects such as progression of cataract, and increase in intraocular pressure, it has become a second line of treatment in macular edema; when the patient is unresponsive to anti-VEGF agents, or they are contraindicated for certain reason.
The inadvertent injection of the implant into the capsular bag is an extremely rare complication, and so far, 13 such cases have been reported worldwide.
The fate of the implant in the intralenticular cavity has been reported to be different in various reports. While Chhabra et al. and Abdolrahimzadeh et al. found the intralenticular implant to still be effective with a gradual resolution of the macular edema, Baskan et al. reported no such improvement at all with further deterioration of vision.
Factors, which could be responsible for such variation, are location of the misdirected implant (whether or not entirely intralenticular), sealing of the posterior capsule by fibrosis at the point of entry of the implant and diabetic control of the patient.
While most authors have opted for a wait and watch approach, followed by a delayed cataract surgery, Fasce et al., Chalioulias and Muqit  and Munteanu and Rosca  opted to go for phacoemulsification immediately.
In our patient, since the visual acuity had dropped from 6/60–4/60 within 1 week in which the patient had presented to us, we planned for immediate phacoemulsification. Also, because OCT scan showed the presence of significant macular edema along with taut posterior hyaloid membrane, he was also an ideal candidate for a combined vitrectomy procedure with removal of the membrane.
However, we decided to go one step ahead and reposit the same implant back into the vitreous cavity. This has been reported only twice before in literature by Munteanu and Rosca  and Chalioulias and Muqit. In their case reports, they have found the reposited implant to have continued beneficial therapeutic effects with a resolution of the cystoid macular edema.
The misdirected implant was extremely fragile and flimsy, and extracting it intact from the lens matter was a surgical challenge. However, once placed back into its position, the implant continued to degrade slowly over time. The visual acuity gradually improved to 6/12, N10; although this could be partially attributed to the removal of the taut posterior hyaloid membrane by vitrectomy, however, the prolonged effect of the intravitreal steroid implant helped to gradually resolve the cystoid macular edema and maintain the effect over a period of 3 months.
The inadvertent injection of the implant into the capsular bag is an extremely rare complication. However, once it occurs, a decision must be taken whether to wait and watch or to intervene immediately. Factors influencing this decision include deterioration of visual acuity, rise in intraocular pressure, progression of cataract as well as the status of the macula. Preserving and re-directing a misdirected dexamethasone implant into the vitreous cavity combined with vitrectomy can be a surgical challenge, but it can help in resolving the DME, as shown in this case.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Fasce F, Battaglia Parodi M, Knutsson KA, Spinelli A, Mauceri P, Bolognesi G, et al. Accidental injection of dexamethasone intravitreal implant in the crystalline lens. Acta Ophthalmol 2014;92:e330-1. [PUBMED]